1. Field of Invention
The present invention relates to an electric device. More particularly, the present invention relates to a tunable current driver for a flat-panel display.
2. Description of Related Art
Flat panel displays are widely used in many industries and homes. A significant benefit of OLED displays over traditional liquid crystal displays (LCDs) is that OLEDs do not require a backlight to function. OLEDs draw far less power and, when powered from a battery, can operate longer on the same charge. Because there is no need to distribute the backlight, an OLED display can also be much thinner than an LCD panel. OLED-based display devices can also be more effectively manufactured than LCDs and plasma displays.
Just like passive-matrix LCD versus active-matrix LCD, OLEDs can be categorized into passive-matrix and active-matrix displays. Active-matrix OLEDs (AMOLED) require a thin film transistor backplane to switch the individual pixel on or off, and can make higher resolution and larger size displays possible. With use, the gate to source voltage (threshold voltage) of the “drive transistor” of active-matrix display may vary, thereby causing a change in the current passing through the LED. This varying current contributes to the non-uniformity in the intensity of the display.
Another contribution to the non-uniformity in intensity of the display can be found in the manufacturing of the “drive transistor”. In some cases, the “drive transistor” is manufactured from a material that is difficult to ensure uniformity of the transistors such that variations exist from pixel to pixel.
For the foregoing reasons, there is a need for a novel tunable current driver and operating method thereof to solve above-mentioned problem about the non-uniformity in the intensity of the display.